Process for the preparation of a cellulose solution for spinning of fibres, filaments or films therefrom

Abstract

An improved process for the preparation of a cellulose solution for spinning of fibers, filaments or films therefrom comprising the steps of: a) activating cellulose in a mixture containing said cellulose, tertiary amine oxide solvent and, water for a period sufficient to allow a swelling of the cellulose by introduction therein of water present in said mixtures, the temperature of said activation step and concentration of solvent being such that the solvent is not converted into its monohydrate state during the step of activation; b) the cellulose, using a activator such as a glycol or a glyme, mixture being subjected to the steps of dissolution of cellulose in the solvent by heating for removal of water so as to convert the solvent into at least its monohydrate form so as to cause a dissolution.

1. An improved process for the preparation of a cellulose solution for spinning of fibres, filaments or films there from comprising in the steps of:
 i) activating cellulose in a mixture containing said cellulose, tertiary amine oxide solvent, activator and water for a period sufficient to allow a swelling of the cellulose by introduction therein of water present in said mixtures, to obtain activated cellulose, the temperature of said activation step and concentration of solvent being such that the solvent is not converted into its monohydrate state during the step of activation; 
 ii) the activated cellulose being subjected to the steps of dissolution of cellulose in the solvent by heating under reduced pressure for removal of water so as to convert the solvent into at least its monohydrate form so as to cause a dissolution. 
 
   
   
     2. A process as claimed in  claim 1 , wherein an activator is added to said mixture, said activator selected from Glycols and Glymes. 
   
   
     3. A process as claimed in  claim 1 , wherein said amine oxide is N-Methyl Morpholine N-Oxide (NMMO). 
   
   
     4. A process as claimed in  claim 1 , wherein said cellulose is selected from rayon pulp and cotton linter pulp. 
   
   
     5. A process as claimed in  claim 1 , wherein said solvent is a mixture of about 40% to about 70% NMMO by weight and about 30% to about 60% water by weight. 
   
   
     6. A process as claimed in  claim 1 , wherein the step of activation is carried out for a period of 20-60 minutes. 
   
   
     7. A process as claimed in  claim 1 , wherein the temperature of said activation step is maintained in the range of 70°-115° C. 
   
   
     8. A process as claimed in  claim 7 , wherein the step of dissolution of the activated cellulose is carried out under reduced pressure. 
   
   
     9. A process as claimed in  claim 1 , wherein the step of dissolution comprises heating the activated cellulose at a temperature of 70° to 120° C. 
   
   
     10. A process as claimed in  claim 1 , wherein the step of dissolution is carried out for 40 to 150 minutes. 
   
   
     11. A process as claimed in  claim 1 , wherein said activator is present in an amount of 0.05% to 3.0% by weight of the cellulose. 
   
   
     12. A process as claimed in  claim 1 , wherein a said cellulose solution contains from about 7% to about 28% by weight dry cellulose, from about 65% to about 80% by weight tertiary amine oxide and from 5% to 15% by weight water.